1. Field of the Invention
The present invention relates to a pad clip for a disc brake of a vehicle. More particularly, the present invention relates to a pad clip improved such that no rattling is present between the pad clip and a friction pad, thereby suppressing generation of vibrations and noisy sounds and providing an increased durability of the disc brake.
2. Description of the Related Art
In a conventional disc brake, a pair of friction pads are slidably mounted on a support member so as to forcibly press a rotor. When the friction pads forcibly press the rotor with the aid of a caliper and a hydraulic cylinder, the friction pads rotate with rotation of the rotor, and the support member receives side edges of the friction pads to effect braking. Since the friction pads are moved so as to be brought into contact with the rotor surfaces, pad clips are installed in anchor portions between the friction pads and the support member in order to reduce a sliding resistance.
The pad clip is put on the anchor face of the support member, which faces each side edge of the friction pad, and it is shaped conforming to a shape of the anchor portions of the support member. The pad clip is extended up to the inner periphery side of each friction pad. At the end of the extended part of the pad clip, there is provided a spring portion which engages with the corner of the inner peripheral side of the friction pad in the run-in side of the rotor. An example of this is disclosed in JP-A-9-229112. As shown in FIG. 7, a pad clip 116 is inserted between a convex portion 112a which transmits a brake torque when the vehicle moves back, and a concave portion 113a. The pad clip 116 includes a first spring portion 116a retained on a support member 113 to urge the convex portion 112a in the rotational and radial directions of the rotor. The first spring portion 116a includes a tongue 116b elastically contacting with the wall 113a1 of the concave portion 113a, which is directed in the radial direction of the rotor. An end 116c of the pad clip which is opposite to the first spring portion 116a includes a second spring portion 116d shaped like a tongue. In a state that the pad clip 116 is installed to the support member 113, the second spring portion 116d is put into a groove 113c, thereby resiliently restricting the rotation of the pad clip 116, which is caused by the first spring portion 116a. The groove 113c is formed in a wall 113a2 of the concave portion 113a of the support member 113. The structure thus constructed prevents the leading edge of the end 116c from contacting the convex portion 112a, and the end 116c does not act as a spring between the support member 113 and the convex portion 112a. As a result, noisy sounds caused by vibrations of the wheels during the running of the vehicle and noisy sounds during the braking operation can be reduced by inexpensive means.
Another example is disclosed in JP-A-57-149337U. As shown in FIGS. 8A and 8B, a pad clip 153 is installed between each end of a friction pad 151 and a support member 152 such that the pad clip ranges from the outer peripheral surface of the friction pad 151 to the inner periphery surface by way of the side end face, to thereby cover the end portion of the friction pad 151. The end of the extending portion of the pad clip 153 extended to the inner periphery portion of the friction pad 151 includes a plate extending from the body of the pad clip 153 in a T-shape in the thickness direction of the friction pad 151. This plate is bent to form a spring portion 154. The spring portion 154 is extended to the underside of the friction pad 151, and urges the inner peripheral surface of the friction pad 151 in the radial direction of the rotor. Therefore, the friction pad 151 is separated from the inner peripheral surface of the support member 152. When the friction pad 151 forcibly presses the rotor and rotates together with the rotor, a rotational moment is generated in the friction pad 151 and a couple of forces to turn the friction pad 151 about the pressed portion are generated. At this time, the spring portion 154 generates an urging force as a counter force to the couple of forces. The body of the pad clip 153 extending to the inner peripheral surface of the friction pad 151 is cut shaped like U to form a raised piece 155 so as to lift the body of the pad clip 153 above from the surface of the support member 152. The raised piece 155 is in direct contact with the surface of the support member 152. With provision of the raised piece 155, a gap between the inner peripheral surface of the friction pad 151 and the surface of the support member 152 opposite to the former is reduced, whereby the spring constant of the spring portion 154 is reduced.
In the conventional U-shaped pad clip 116 described in the publication of JP-A-9-229112, the first spring portion 116a is assembled to the convex portion 112a, and it is used while being bent. With this, the gap is reduced. When a force acts on the first spring portion 116a, a reaction force is generated therein and utilized to reduce rattle sound. At this time, the pad clip 116 and the convex portion 112a of the friction pad are coupled together. Therefore, the former forcibly hits the support member 113. This reduces an endurance of the pad clip 116. Further, the groove 113c is formed in the wall 113a2 of the concave portion 113a of the support member 113, and the second spring portion 116d is brought into engagement with the groove 113c. This makes the structure complicated and difficult to assemble, and this also increase the step of manufacturing steps.
In the pad clip 153 described in the publication of JP-A-57-149337U, the spring portion 154 is indispensably used which is formed by bending the T-shaped plate which is extended to the inner peripheral surface of the friction pad 151 beyond the anchor face by the friction pad 151 and the support member 152, and to under the inner peripheral surface of the friction pad 151. Use of the spring portion 154 gives rise to difficulty in a plate forming process of the spring portion. A satisfactory length ranging from the convex-concave fitting structure to the inner peripheral portion of the friction pad 151 must be secured. This results in consumption of much material, and leads to increase of cost to manufacture. The raised piece 155 is formed in the body of the pad clip 153 in order to reduce the spring constant of the spring portion 154. Forces applied to the spring portion 154 act on the raised piece 155. In this case, the raised piece 155 receives all the forces, and as a result, problem exists in its strength.